Circulating Tumor Cells
May 6, 2009
1:00 p.m. – 3:00 p.m. EST

1:10-1:50 Circulating Tumor Cell Assays: A Prognostic and Predictive Factor For Breast, Prostate And Colon CancerHerbert A Fritsche, Ph.D., Professor and Chief, Clinical Chemistry, Department of Laboratory Medicine, The University of Texas, M.D. Anderson Cancer CenterThe current hypothesis of cancer metastasis proposes that tumor cells escape into the blood and circulate until they are either eliminated by host response mechanisms or until they find an environment in which to reside in a dormant condition and to proliferate at a later time. Thus, the detection of circulating tumor cells may represent an early indication of micro-metastasis or of aggressive tumors which are able to shed tumor cells into the blood. The circulating tumor cells can be captured using antibody labeled magnetic beads, either in positive or negative selection schema. After the circulating tumor cells are isolated, they may be characterized by immunohistochemistry and counted. Alternatively, these cells may be characterized by gene expression analysis using RT-PCR. One of the CTC detection methods (Veridex Inc, Cell Search Assay) has been cleared by the US FDA for use as a prognostic test in patients with metastatic cancers of the breast, prostate and colon. In these cases of metastatic cancer, the pre-treatment presence of tumor cells is prognostic of a poor outcome, at any time during the course of the disease. Furthermore, in metastatic breast cancer patients, the presence of tumor cells at the end of the first course of chemotherapy, is predictive of treatment failure. Thus, the CTC test may permit the oncologist to make an early decision to discontinue first line therapy for metastatic breast cancer and pursue more aggressive alternative treatments. We have addressed the practical aspects of routine testing for CTC’s using the Veridex Cell Search method. We have established the long-term precision of the method CV=18% at a mean value = 44 cells and by recovery of added cells (recovery = 80-90% at 5-10 added cells). We have also confirmed the stability of CTC’s in the Cell Save tube for up to 3 days at room temperature. Our data continue to demonstrate the prognostic value of CTC measurement for breast cancer patients. In a study of 124 metastatic breast cancer patients, those with negative CTC had a median overall survival of 28.3 months, while those with positive CTC had a median survival of only 12.8 months. The Veridex Cell Search system provides a reliable assessment of CTC and its use in the clinical management of breast cancer. We have also evaluated the Adnagen Breast Cancer Cell Select and Detect assay for CTC detection. The method uses multi-antigen cell capture with antibody labeled magnetic beads, followed by RT-PCR characterization of selected genes. This assay may compliment the Cell Search assay for tumor cell detection in blood. Other CTC assays based on new capture technologies are currently in development.

2:00-2:40 Advances in Circulating Tumor Cell Technology and the Application to Clinical ManagementMartin Fleisher, Ph.D., Chair, Department of Clinical Laboratories, Memorial Sloan-Kettering Cancer Center
Detecting Circulating Tumor Cells (CTC) in peripheral blood of patients with cancer has become a clinically relevant and important prognostic biomarker and has been shown to be a predictive biomarker post-therapy. But, key to the use of CTCs as a biomarker is the technology designed to enrich cancer cells from peripheral blood. Currently, only one platform, the Veridex CellTrack Analyzer, has been FDA approved for use in monitoring therapeutic response in patients with breast, prostate and colon cancer. This technology relies on the expression of epithelial cellular adhesion molecular (EpCAM) by epithelial cells and the isolation of these cells by immunomagnetic capture using anti-EpCAM antibodies. Enriched CTCs are identified by immunofluorescence. Every new technology has shortcomings, and the reliance on cancer cells to express sufficient EpCAM to enable capture may affect the role of this technology in future clinical use. Heterogeneous downregulation of epithelial surface antigen in invasive tumor cells has been reported. Alternative methods to detect CTC are being developed. These new methods include, 1) flow cytometry that sorts cells by size and surface antigen expression, 2) CTC microchips that are designed to capture CTC as whole blood flows past EpCAM-coated mirco-posts, and 3) enrichment by filtration using filters with a pore size of 7-8 µm, that permits smaller red blood cell, leukocytes, and platelets to pass, but captures CTCs that have diameters of about 12-15 µm. The evolution of the CTC technology will be critical in the emerging area of targeted therapy. New technologies will explore the association between CTC and the genomic information that can be gleaned from these isolated cells. There is ample data on the use of CTC for FISH analysis and it relationship to outcome and drug development. This webinar will demonstrate the relationship between new CTC technology as a “liquid biopsy” and molecular profiling to aid drug development.

2:40-3:00 Discussion with the Speakers

About the Speakers:

Martin Fleisher, Ph.D., Chair, Department of Clinical Laboratories, Memorial Sloan-Kettering Cancer CenterMartin Fleisher, Ph.D., is the Chairman of the Department of Clinical Laboratories and Chief of the Clinical Chemistry Service at the Memorial Sloan-Kettering Cancer Center in New York City. Dr. Fleisher received his doctorate degree in biochemistry from New York University. Dr. Fleisher has over thirty years experience in discovery and application of new tumor markers and biomarkers for the early detection of cancer. His interest in biomarkers was initiated by the validation of carcinoembryonic antigen (CEA) in colon cancer. In 1973 he published the definitive paper on the comparative analytical aspects of three different CEA assays and pointed out the shortcomings of this tumor marker. His seminal work on the relationship between breast cancer and cystic mastopathy involved over 80 analytes, and included biomarkers consisting of peptides, proteins, enzymes, hormones, immunoglobulins and trace metals. More than 1500 breast cyst fluids were analyzed and the association of certain analytes to breast cancer was statistically estimated. He has investigated the use of biomarkers, such as urokinase plasminogen activator (uPA) and plasminogen activator inhibitor 1(PAI-1) as prognostic markers in women with node negative breast cancer.

Dr. Fleisher has spent his career in the discovery, development and clinical association of biomarkers that help in the early detection of cancer. He developed chromatographic methods for the determination of urinary metabolites used in the early detection and monitoring of neuroblastomas in children. In collaboration with his neuro-oncology colleagues, he developed a panel of tumor markers in cerebrospinal fluid that help identify the presence of central nervous system tumors (leptomeningeal metastasis). This panel of biomarkers (AFP, CEA and LDH isoenzyme 5) is still in use today. In collaboration with his gastrointestinal oncology colleagues, he developed and patented an accurate, highly sensitive test for fecal occult blood that was unaffected by diet, hence reducing false positive test results. As a member of the International Consortium on Colorectal Cancer and the National Polyp Study Workgroup, he developed and standardized the quality control and clinical use of fecal occult blood testing in the U.S., Europe, Australia, and Japan. The successful use of the Hemoccult slide test for detecting early colon cancers is based on the work that Dr. Fleisher and his colleagues published in 1980 and 1983. The use of high dose methotrexate (MTX) in treating patients with a variety of cancers required the accurate and rapid measurement of MTX in blood and spinal fluid. Dr. Fleisher developed a semi-automated analytical procedure for the rapid measurement of MTX based on dihydrofolate reductase inhibition, which parallels the pharmacological mode of action of MTX on a cellular level. The assay is currently used for the measurement of all MTX and anti-fol analogs at MSKCC. He has developed and validated assays for the management of patients with B-cell dyscrasias with amyloidosis (free serum lambda and kappa light chains), biomarkers helpful in the prognostic evaluation of patients with ovarian cancer (YKL-40 and MMP-9), the use of circulating tumor cells (CTC) in patients with metastatic prostate cancer, and the development of a bone marker panel (osteocalcin, bone specific alkaline phosphatase, N-telopeptide, and Vitamin D) to detect the affects of tyrosine kinase inhibitors (imatinib) in patients with CML and GIST (NEJM May 2006). Dr. Fleisher’s research focus is on the development of new, rapid, and inexpensive bioassays for detecting and monitoring cancer.

Herbert A. Fritsche, Ph.D., Professor and Chief, Clinical Chemistry, Department of Laboratory Medicine, The University of Texas, M.D. Anderson Cancer CenterDr. Herbert Fritsche is a native of Houston, Texas where he received his early education and a B.S. degree in Chemistry from the University of Houston in 1963. He received an MS degree (1965) and Ph.D. degree (1968) in Chemistry from Texas A & M University. From 1967 to 1969, he served on active military duty as Captain, Assistant Chief, and then Chief, Clinical Chemistry at the First U.S. Army Medical Laboratory in Ft. Meade, Md. In 1969, he accepted the position as Chief of Clinical Chemistry at M. D. Anderson Cancer Center and has served in that capacity for the past 39 years. In that capacity, Dr. Fritsche directs the clinical chemistry testing operations for the M.D. Anderson Hospital and outpatient clinics; participates in the education of medical fellows, pathology residents, graduate students and medical technology students; and conducts an active research program in the development and validation of cancer diagnostics. He has served in all elected positions in the Texas Section of the AACC, and he has served on and chaired the National Education Committee and the Education Committee of the Immunology Division of the American Association for Clinical Chemistry (AACC). He has served on many of the committees of the AACC, and of the NACB, and numerous review committees for the National Cancer Institute. He served as National President of the Clinical Ligand Assay Society, and the Texas Medical Centre Chapter of Sigma Xi. Currently, he is a member of the editorial board of six journals, a Fellow in the National Academy of Clinical Biochemistry (NACB), a member of the Tumour Marker Expert Panel (American Society of Clinical Oncology), the Tumour Marker Guidelines Committee for (NACB), the Technology Expert Panel for Blue Cross Blue Shield, and he is an active member of five professional societies. He is the recipient of the 1979 Outstanding Clinical Chemist Award from the Texas Section-AACC, the 1992 National AACC Award for Education, the 1997 Johnson and Johnson Award for Outstanding Research from the NACB, the CLAS Distinguished Scientist Award in 1999 and the 2006 Morton K. Schwartz AACC Award for Research Contributions in Cancer Diagnostics. He has lectured at many international meetings and has published more than 180 manuscripts and 30 book chapters in the field of cancer diagnostics. He is a member of the scientific advisory boards for seven companies, he holds four patents and two patent applications, is the co-author of a textbook on Tumour Markers, published by AACC press, and he is the Meeting Director of a Biennial Conference on Cancer Diagnostics sponsored by the M.D. Anderson Cancer Center.